1. Technical Field
The present invention relates to a liquid ejecting device and a method of controlling a liquid ejecting device, and more particularly, to a liquid ejecting device having the configuration in which a liquid is ejected in a state that a long liquid ejecting head, in which a nozzle group is disposed in a length corresponding to a maximum width of a landing target at a predetermined pitch, is disposed to be fixed in a position with respect to a device main body or a liquid is ejected by moving a liquid ejecting head in the print direction without transporting the landing target and a method of controlling the liquid ejecting device.
2. Related Art
Liquid ejecting devices are devices that have a liquid ejecting head for ejecting a liquid and eject various types of liquids from the liquid ejecting head. As a major liquid ejecting device, for example, there is an image recording device such as an ink jet printer that performs a record operation by ejecting (emitting) and landing ink having a liquid phase to a landing target such as a recording sheet. In addition, recently, the liquid ejecting device is not limited to the image recording device and is applied to various types of manufacturing apparatuses. For example, in an apparatus for manufacturing a display such as a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, or an FED (Field Emission Display) the liquid ejecting device is used for ejecting various types of materials such as a coloring material or an electrode having a liquid phase to a pixel forming area, an electrode forming area, or the like.
An ink jet recording device (so called a printer) that is one type of the liquid ejecting devices has an ink jet recording head (one type of a liquid ejecting head, so called a serial head) that is shorter than the width of a recording medium, a head moving mechanism that reciprocates the record head in the main scanning direction, a transport mechanism (recording medium transporting mechanism) that performs a sub scanning operation by sending the recording medium (landing target) such as a recording sheet in the direction perpendicular to the main scanning direction, and the like. The ink jet recording device is configured to record an image or the like in the recording medium by alternately repeating ejection of ink droplets in the main scanning of the record head and transporting (sub scanning) of the recording medium. However, since there is a limit in the scanning speed of the record head, there is a problem for a device of this type that a long time period is needed, for example, in a case where an image is recorded on the entire surface of the recording medium that has relatively large size.
Thus, recently, a device that is configured to eject ink in a state that a long record head (one of line-type liquid ejecting heads, hereinafter referred to as a line-type head) in which a nozzle group is disposed in a length corresponding to a maximum width of a recording medium at a predetermined pitch is fixed without being moved with respect to a device main body has been proposed (JP-A-6-183029 (FIGS. 2 to 4)). According to such a configuration, movement of the record head in the main scanning direction is not needed, and recording an image or the like can be performed only by transporting the recording medium in the sub scanning direction. As a result, according to the configuration, a record time can be shortened, compared to a configuration using a serial head.
In addition, a printer in which a plurality of heads ejecting ink droplets of a same color is disposed in parallel, a plurality of ejection stages (record stages) is disposed along the direction perpendicular to the direction of the parallel disposition, and an image or the like is sequentially recorded in the recording medium by using record heads, which are disposed for each ejection stage, in each ejection stage while relatively moving the record head and the landing target in the perpendicular direction has been proposed.
For example, as shown in FIG. 12, there is a configuration in which line-type record heads 51a to 51d corresponding to colors of black (K), cyan (C), magenta (M) and yellow (Y) are disposed in ejection stages 52a to 52d along the transport path of a recording sheet 54 and an image or the like is formed in the recording sheet 54 for each color while the recording sheet 54 is transferred among transport belts 53a to 53d of the ejection stages. In the transport belt in each ejection stage, a linear scale 55 and a linear encoder 56 having a sensor unit that optically detects the scale pattern of the linear scale 55 are disposed, and a record operation is controlled based on a detection signal output from the linear encoder 56.
Under such a configuration, there is a case where the transport speed of the recoding sheet 54 changes due to a mechanical error of a transport unit including the transport belt or the like. In addition, in transferring the recording sheet 54 among the transport units of the ejection stages, the position of the recording sheet 54 in the direction (direction of alignment of the nozzles) perpendicular to the transport direction may be deviated. The transport error may cause the deviation of ink landing positions in the recording sheet 54 among the ejection stages. As a result, there is a possibility that the image quality of the image recorded in the recording sheet 54 deteriorates. In addition, when a print operation is performed by moving the line-type record heads 51a to 51d in the print direction without transporting the recording sheet 54 in the transport direction, if the recording sheet 54 is deviated in the print direction, the landing position of ink in the recording sheet 54 may be deviated. As a result, there is a possibility that the image quality of the image recorded in the recording sheet 54 deteriorates, as in the above-described case in which the recording sheet 54 is transported.
FIGS. 13A to 13D are diagrams represented by enlarging a part of an image P of the recording sheet 54 in a third ejection stage 52c in the above-described configuration. When the positional deviation of the recording sheet 54 in the transport direction among the ejection stages or the positional deviation of the recoding sheet in the direction perpendicular to the transport direction is not generated at all, as shown in FIG. 13A, in this example, a pixel Px1 (for example, a pixel of cyan) formed in a second ejection stage 52b and a pixel Px2 (for example, a pixel of magenta) formed by the third ejection stage 52c are orderly disposed in a zigzag pattern vertically and horizontally. However, when any countermeasure is not taken under the configuration, there is a rare case that the deviation of landing positions in both vertical and horizontal directions is not generated at all.
For example, when the positional deviation of the recording sheet 54 in the transport direction is generated between the second ejection stage 52b and the third ejection stage 52c, as shown in FIG. 13B, a deviation of the landing positions of the pixel Px1 and the pixel Px2 is generated. In addition, when the positional deviation of the recording sheet 54 in the direction of alignment of nozzles is generated between the second ejection stage 52b and the third ejection stage 52c, that is, when a state in which the recording sheet 54 meanders is formed, as shown in FIG. 13C, a deviation of landing positions in the direction of alignment of nozzles is generated between the pixel Px1 and the pixel Px2. Practically, as shown in FIG. 13D, the positional deviation is frequently generated in both directions of the transport direction and the direction of alignment of nozzles. When the deviation of the landing positions is generated, other pixels are overlapped with each other, and accordingly, the color may change. In addition, by forming a gap between the pixels, there is a possibility that the image becomes rough.